Fuel atomization device in diesel pile driver



1967 SHOJIRO NISHIMURA ETAL 3,303,392

FUEL ATOMIZATION DEVICE IN DIESEL FILE DRIVER Filed June 23, 1964 PRIOR4/"? T PR/OR ART 2O '2 I; g5 g 18 I ,1 p I4 INVENTOR5 SHOJIRO NISHIMURA, MASAO,

ISHIZAKI, AND HIROTOSHI BABA.

ATTO Y.

United States Patent 3,393,892 FUEL ATOMIZATION DEVICE IN DIESEL PHEDRIVER Shojiro Nishimura, Ashiya-shi, Masao Ishizaki, Nada-kn, Kobe, andHirotoshi Babe, Higashi-Nada-ku, Kobe, Japan, assignors to Kobe SteelWorks, Ltd, Kobe, Japan Filed June 23, 1964, Ser. No. 377,355 Clairnsprior-i application Japan, June 24, 1963, 38/4633!) 2 Claims. (Cl.173-133) The present invention relates to a fuel atomization device foruse in a diesel pile driver and more particularly relates to a fuelatomization device for a diesel pile driver of the type in which theimpact portions of the hammer and anvil of the diesel pile driver areuniquely designed so that the fuel within the pile hammer is perfectlyatomized and thereby the driving efficiency of such pile driver isgreatly improved and, also, instability in the driving of the hammer,which has been one of the most serious drawbacks associated with theprior art diesel pile drivers, is eliminated.

In the prior art diesel pile driver as shown in FIGS. 1 and 2, hammer 1is generally raised by a suitable actuating means and when the hammerhas reached a predetermined height the hammer automatically drops.

As hammer 1 drops, it actuates cam 3 of fuel pump 2 so as to spray apredetermined amount of fuel onto anvil 4 and at the same time the airbelow air supply-exhaust bores 5 is entrapped by oncoming piston ring 6and such air is further highly compressed by the dropping hammer 1.Thereafter, when hammer head 7 strikes against anvil 4 the sprayed fuelis atomized and distributed throughout the compressed air maintained ata high temperature and a high pressure and instantaneously andexplosively burns. The high pressure caused by the collision between thehammer and anvil as well as the explosive combustion of the fuel impartsdriving energy to the pile to be driven and simultaneously, theremainder of the combustion gas energy lifts the hammer to its dropposition again. By repeating this diesel cycle a pile can becontinuously driven into the ground until it reaches a desired depth.

When the pile is driven by a pile driver of the prior art in the mannerset forth above, if the pile is being driven in against relativelylittle resistance, because of, for instance, comparatively soft ground,a pile of comparatively small diameter or a comparatively light pile,the distance the pile moves each time the hammer strikes is great andthe impact of hammer or anvil does not fully atomize the fuel. Thisresults in incomplete combustion. In this case, the return stroke of thehammer after its collision with anvil 4 is shortened and with a shorthammer stroke, cyclic fuel explosions fail to take place and a steadydriving operation by the hammer is not ensured. Because of this drawbacka specific actuating means has to be employed in the prior art dieselpile driver to help lift hammer 1 up after each blow by the hammer; thislowers the operative efficiency of the pile driver to a serious extent.

If one watches a conventional diesel pile driver while it is driving apile into soft ground, he will note that anvil 4 sinks into the groundtogether with the pile before falling hammer It strikes against anvil 4again, the result hein a decrease in relative speed between the hammerand anvil. This decrease in relative speed between the hammer and anvilcorrespondingly reduces the force available for compressing the fuel oilbetween the hammer and anvil, and accordingly, the fuel is imperfectlyatomized and the particles of fuel do not become sufficiently fine.Furthermore, because of the insufl'icient impact force, the atomizedfuel is not evenly distributed throughout the compressed air. Thecombination of the above drawbacks leads to imperfect ignition of thefuel.

Patented Feb. 14, 1967 ice Since the relative speed between the hammerand anvil depends upon the size of the hammer in relation to the pilesto be driven by the hammer and on the condition of the ground where thepiles are driven, in order to improve the operative efiiciency of aconventional driver, it seemed evident that the hammer and anvil wouldhave to be improved.

For example, the shape of the combustion chamber and the shapes of theimpact surfaces of the hammer and anvil might be improved.

With the above facts in mind, the shapes of the impact surfaces of thehammer and anvil were changed and the present invention was developed toprovide an efficient diesel pile driver with an atomization device whichatomizes the fuel perfectly.

The present invention provides an improved atomization device in whichthe impact surfaces (contact surfaces) of the hammer and anvil aredesigned to have unique configurations, that is, the top surface of theanvil is provided with a centrically disposed convexly shaped projectionand an annular recess surrounding said projection whilst the bottomsurface of the hammer is pro vided with a centrically disposed recessand an annular ridge, said center recess and annular ridge being opposedand complementary to said center convexly shaped projection and annularrecess of the anvil respectively, whereby the fuel on the anvil may beaccumulated in the vicinity of the inner wall of the cylinder.

Furthermore, according to the present invention, since the fuel isaccumulated within the annular recess on the top of the anvil, the fuelis compressed in the vicinity of the inner wall of the cylinder or thecombustion chamber, and accordingly, fuel spraying pressure in the pathalong which the fuel is outwardly sprayed is not decreased, resulting inhighly efiicient atomization of the fuel.

In the prior art fuel atomization device as shown in FIGS. 1 and 2, theOpposing impact surfaces of the hammer and anvil are semicircular inshape. In contrast, the specially shaped impact surfaces of the hammerand anvil of the present invention make the hammer-anvil combination ofthe present invention superior to the prior art ram and anvil.

Having briefly described the invention, a more detailed description ismade below by reference to typical embodiments of the invention asillustrated in the drawings.

In the drawings:

FIG. 1 is a vertical cross-sectional view of a prior art diesel piledriver showing the inner arrangement thereof;

FIG. 2 is a vertical cross-sectional view of the fuel atomization deviceprovided within said pile driver of FIG. 1;

FIG. 3 is a vertical cross-sectional view of a fuel atomization deviceaccording to the present invention;

FIG. 4 is a schematically view showing the manner in which the fuel isatomized in said atomization device of FIG. 3; and

FIG. 5 is a vertical cross-sectional view of a modified atomizationdevice of the present invention.

Reference will now be made to the preferred embodiment of the presentinvention shown in FIGS. 3 and 4. In this embodiment hammer 10 isdisposed within cylinder 11 for reciprocal up and down movement therein.Anvil 12 fits in at the lower end portion of cylinder 11 for frictionalmovement with respect to the cylinder for a predetermined distance.Hammer 10 is provided with an integrally formed downwardly projectingfoot portion 13 at its bottom end and foot portiton 13 has a diameter dwhich is smaller than the diameter D of the hammer itself. The top endof anvil 12 which is opposed to the bottom end of hammer 10 or the footportion 13 is formed with a dish-like recess 14 of diameter d which isthe same 3 as the diameter d of foot portiton 13. The bottom surface offoot portion 13 and the bottom surface of dishlike recess 14 form theimpact surfaces of hammer and anvil 12, respectively.

Dish-like recess 14 is provided with a projection 15 having a suitableheight at its center and a valley-shaped annular recess 16 surroundingcenter projection 15. The top surface of projection 15 is connected withthe bottom surface of annular recess 16. The cross-sectional shape ofprojection 15 is preferably of a gentle curve as seen in FIG. 3, butalternatively the cross-sectional shape of the projection may be angularas seen in FIG. 5.

On the other hand, the bottom surface of hammer foot portion 13 isprovided with a circular concave groove 17 in its center and saidconcave groove 17 has a shape complementary to the shape of projection15 at anvil recess 14. Annular ridge 18 is provided surrounding concave17 and ridge 18 has a shape complementary to the shape of annular recess16.

Therefore, when the bottom surface of hammer foot portion 13 comes intocontact with the bottom surface of anvil recess 14, a contact surfacecomprised of centrally projecting surface 19 and annular recess 20surrounding projecting surface 19 is formed, as seen in FIG. 4. In theatomization device as described above, the fuel which has been sprayedfrom the fuel pump nozzle into the cylinder falls onto anvil 12, entersdish-like recess 14 and finally accumulates within annular recess 16. Ashammer 10, which has been previously raised, drops, foot portion 13 ofhammer 10 enters dish-like recess 14 of anvil 12 to gradually compressthe air and fuel there and when the hammer and anvil collide with eachother the fuel is caused to be atomized and scattered in all directions.

The manner in which the fuel is atomized and scattered in all directionsis shown in FIG 4. If both the contact surfaces of the hammer and anvilare formed as complemental spherical shapes, the fuel accumulates itselfat the center of the top of the anvil (see FIG. 2), and accordingly, inorder that the fuel be atomized and scattered in all directions in sucha prior art device, the fuel requires a path L as shown in FIG. 2.However, if the recess 16 where the fuel accumulates itself is formed asan annular shape, the fuel is scattered by way of a path 1 (FIG. 4)which is substantially shorter than the path L in FIG. 2.

In order that the fuel scatters into the cylinder, the fuel must passalong the path L or I but, at this time, since viscosity of the fuelsubstantially resists such passing of the fuel the shorter the path, thelesser the resistance by the fuel viscosity, and accordingly, with theshorter path I, there will be little loss of the pressure in scatteringthe fuel and the atomization of the fuel can be perfectly performed.This is one important advantage to be obtained by the present invention.

When the recess 16 which is provided for accumulating the fuel on thetop of the anvil 12 is formed with an annular shape, the surface 18 ofannular ridge 18 has come to contact the fuel surface within the annularrecess 16 of anvil 12 first during the downward stroke of hammer 10. Theair entrapped between the hammer and anvil inwardly of the contactingcircle defined by surface 18 the fuel in and recess 16 is sealed thereinand compressed in situ, and accordingly, the pressure exerted by thecompressed air serves to scatter the fuel outwardly. As a resuit, thefuel is scattered radially and outwardly with a substantially greatforce, thereby ensuring perfect atomization'of the fuel. The atomizedfine particles of fuel are evenly distributed into the cylinder andpositively ignited. This is another advantage of the present invention,which can not be expected in the prior art atomization device of FIGS. 1and 2. The shape of the bottom end surface of the hammer and that of theupper end surface of the anvil are designed so they may not becompletely complementary to each other, but leave a slight clearancebetween the upper surface of the projection 15 and the bottom surface ofthe concave 17.

As is evident from the foregoing, the atomization device by the presentinvention can effect perfect atomization, thereby eliminating the defectsuch as poor driving efficiency due to insufficient upward movement ofthe hammer which is caused by imperfect atomizatiton of the fuel. Thediesel pile driver incorporating the novel atomization device can notonly be expected to perform efficiently on soft grounds, but also thehammer can be continuously driven with a great horse-power through theimproved atomizing efiiciency, and in addition, such a hammer canprovide a maximum driving force obtainable with a fixed amount of fuel.Thus, the diesel pile driver incorporating the novel atomization deviceby the present invention has a great utility.

It should be understood that the present invention is not limited to thedetails of the foregoing descriptions and illustrations of the typicalembodients of the invention, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention as described hereinabove and as defined in the appendedclaims.

What is claimed is:

1. A fuel atomization device and diesel pile driver, comprising acylinder, a hammer disposed within said cylinder for reciprocal movementand having an impact surface at the lower end thereof, and an anvil fitin said cylinder at the lower end for a limited frictional movement andhaving an impact surface at the upper end thereof, said upper end impactsurface of the anvil being opposed to said impact surface of the hammerand adapted to accumulate fuel thereon so that when said hammer dropsand strikes against said anvil said fuel is atomized, said lower endimpact surface of the hammer being provided with a centrally positionedconcave circular groove and an annular ridge surrounding said groove,said upper end impact surface of the anvil being provided with acentrally positioned convexly shaped projection and an annular recesssurrounding said projection whereby the fuel may be accumulated in thevicinity of the inner wall of said cylinder.

2. A fuel atomization device and diesel pile driver, comprising acylinder, a hammer disposed within said cylinder for reciprocal'movementand having an impact surface at the lower end thereof, and an anvil fitin said cylinder at the lower end for a limited frictional movement andhaving an impact surface at the upper end thereof, said upper end impactsurface of the anvil being opposed to said impact surface of the hammerand adapted to accumulate fuel thereon so that when said hammer dropsand strikes against said anvil said fuel is atomized, said lower endimpact surface of the hammer being provided with a centrally disposedrecess having a square cross-section and an annular ridge surroundingsaid recess, said upper end impact surface of the anvil being providedwith a centrally disposed projection having a square cross-section andan annular recess surrounding said projection whereby the fuel may beaccumulated in the vicinity of the inner wall of said cylinder.

References Cited by the Examiner UNITED STATES PATENTS 2,093,634 9/1937Cordes 173133 2,208,730 7/1940 Pfeiffer 173-133 2,633,832 4/1953 Sparlin173133 2,740,385 4/1956 Hoage 173135 FRED C. MATTERN, JR., PrimaryExaminer. L. P. KESSLER, Assistant Examiner.

1. A FUEL ATOMIZATION DEVICE AND DIESEL PILE DRIVER, COMPRISING ACYLINDER, A HAMMER DISPOSED WITHIN SAID CYLINDER FOR RECIPROCAL MOVEMENTAND HAVING AN IMPACT SURFACE AT THE LOWER END THEREOF, AND AN ANVIL FITIN SAID CYLINDER AT THE LOWER END FOR A LIMITED FRICTIONAL MOVEMENT ANDHAVING AN IMPACT SURFACE AT THE UPPER END THEREOF, SAID UPPER END IMPACTSURFACE OF THE ANVIL BEING OPPOSED TO SAID IMPACT SURFACE OF THE HAMMERAND ADAPTED TO ACCUMULATE FUEL THEREON SO THAT WHEN SAID HAMMER DROPSAND STRIKES AGAINST SAID ANVIL SAID FUEL IS ATOMIZED, SAID LOWER ENDIMPACT SURFACE OF THE HAMMER BEING PROVIDED WITH A CENTRALLY POSITIONEDCONCAVE CIRCULAR GROOVE AND AN ANNULAR RIDGE SURROUNDING SAID GROOVE,SAID UPPER END IMPACT SURFACE OF THE ANVIL BEING PROVIDED WITH ACENTRALLY POSITIONED CONVEXLY SHAPED PROJECTION AND AN ANNULAR RECESSSURROUNDING SAID PROJECTION WHEREBY THE FUEL MAY BE ACCUMULATED IN THEVICINITY OF THE INNER WALL OF SAID CYLINDER.